Ginkgo  Generated from pipelines/1556235455 branch based on develop. Ginkgo version 1.9.0
A numerical linear algebra library targeting many-core architectures
Classes | Public Types | Public Member Functions | Static Public Member Functions | Friends | List of all members
gko::experimental::reorder::Rcm< IndexType > Class Template Reference

Rcm (Reverse Cuthill-McKee) is a reordering algorithm minimizing the bandwidth of a matrix. More...

#include <ginkgo/core/reorder/rcm.hpp>

Inheritance diagram for gko::experimental::reorder::Rcm< IndexType >:
[legend]
Collaboration diagram for gko::experimental::reorder::Rcm< IndexType >:
[legend]

Classes

struct  parameters_type
 

Public Types

using index_type = IndexType
 
using permutation_type = matrix::Permutation< index_type >
 
- Public Types inherited from gko::EnablePolymorphicAssignment< Rcm< IndexType > >
using result_type = Rcm< IndexType >
 
- Public Types inherited from gko::ConvertibleTo< Rcm< IndexType > >
using result_type = Rcm< IndexType >
 

Public Member Functions

const parameters_typeget_parameters ()
 Returns the parameters used to construct the factory. More...
 
std::unique_ptr< permutation_typegenerate (std::shared_ptr< const LinOp > system_matrix) const
 
- Public Member Functions inherited from gko::EnableAbstractPolymorphicObject< Rcm< IndexType >, LinOpFactory >
std::unique_ptr< Rcm< IndexType > > create_default (std::shared_ptr< const Executor > exec) const
 
std::unique_ptr< Rcm< IndexType > > create_default () const
 
std::unique_ptr< Rcm< IndexType > > clone (std::shared_ptr< const Executor > exec) const
 
std::unique_ptr< Rcm< IndexType > > clone () const
 
Rcm< IndexType > * copy_from (const PolymorphicObject *other)
 
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, Rcm< IndexType > > * copy_from (std::unique_ptr< Derived > &&other)
 
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, Rcm< IndexType > > * copy_from (const std::unique_ptr< Derived > &other)
 
Rcm< IndexType > * copy_from (const std::shared_ptr< const PolymorphicObject > &other)
 
Rcm< IndexType > * move_from (ptr_param< PolymorphicObject > other)
 
Rcm< IndexType > * clear ()
 
- Public Member Functions inherited from gko::LinOpFactory
std::unique_ptr< LinOpgenerate (std::shared_ptr< const LinOp > input) const
 
- Public Member Functions inherited from gko::PolymorphicObject
PolymorphicObjectoperator= (const PolymorphicObject &)
 
std::unique_ptr< PolymorphicObjectcreate_default (std::shared_ptr< const Executor > exec) const
 Creates a new "default" object of the same dynamic type as this object. More...
 
std::unique_ptr< PolymorphicObjectcreate_default () const
 Creates a new "default" object of the same dynamic type as this object. More...
 
std::unique_ptr< PolymorphicObjectclone (std::shared_ptr< const Executor > exec) const
 Creates a clone of the object. More...
 
std::unique_ptr< PolymorphicObjectclone () const
 Creates a clone of the object. More...
 
PolymorphicObjectcopy_from (const PolymorphicObject *other)
 Copies another object into this object. More...
 
template<typename Derived , typename Deleter >
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, PolymorphicObject > * copy_from (std::unique_ptr< Derived, Deleter > &&other)
 Moves another object into this object. More...
 
template<typename Derived , typename Deleter >
std::enable_if_t< std::is_base_of< PolymorphicObject, std::decay_t< Derived > >::value, PolymorphicObject > * copy_from (const std::unique_ptr< Derived, Deleter > &other)
 Copies another object into this object. More...
 
PolymorphicObjectcopy_from (const std::shared_ptr< const PolymorphicObject > &other)
 Copies another object into this object. More...
 
PolymorphicObjectmove_from (ptr_param< PolymorphicObject > other)
 Moves another object into this object. More...
 
PolymorphicObjectclear ()
 Transforms the object into its default state. More...
 
std::shared_ptr< const Executorget_executor () const noexcept
 Returns the Executor of the object. More...
 
- Public Member Functions inherited from gko::log::EnableLogging< PolymorphicObject >
void add_logger (std::shared_ptr< const Logger > logger) override
 
void remove_logger (const Logger *logger) override
 
void remove_logger (ptr_param< const Logger > logger)
 
const std::vector< std::shared_ptr< const Logger > > & get_loggers () const override
 
void clear_loggers () override
 
- Public Member Functions inherited from gko::log::Loggable
void remove_logger (ptr_param< const Logger > logger)
 
- Public Member Functions inherited from gko::EnablePolymorphicAssignment< Rcm< IndexType > >
void convert_to (result_type *result) const override
 Converts the implementer to an object of type result_type. More...
 
void move_to (result_type *result) override
 Converts the implementer to an object of type result_type by moving data from this object. More...
 
- Public Member Functions inherited from gko::ConvertibleTo< Rcm< IndexType > >
void convert_to (ptr_param< result_type > result) const
 
void move_to (ptr_param< result_type > result)
 

Static Public Member Functions

static parameters_type build ()
 Creates a new parameter_type to set up the factory.
 

Friends

class EnablePolymorphicObject< Rcm< IndexType >, LinOpFactory >
 
class enable_parameters_type< parameters_type, Rcm< IndexType > >
 

Detailed Description

template<typename IndexType = int32>
class gko::experimental::reorder::Rcm< IndexType >

Rcm (Reverse Cuthill-McKee) is a reordering algorithm minimizing the bandwidth of a matrix.

Such a reordering typically also significantly reduces fill-in, though usually not as effective as more complex algorithms, specifically AMD and nested dissection schemes. The advantage of this algorithm is its low runtime.

The class is a LinOpFactory generating a Permutation matrix out of a Csr system matrix, to be used with Csr::permute(...).

There are two "starting strategies" currently available: minimum degree and pseudo-peripheral. These strategies control how a starting vertex for a connected component is chosen, which is then renumbered as first vertex in the component, starting the algorithm from there. In general, the bandwidths obtained by choosing a pseudo-peripheral vertex are slightly smaller than those obtained from choosing a vertex of minimum degree. On the other hand, this strategy is much more expensive, relatively. The algorithm for finding a pseudo-peripheral vertex as described in "Computer Solution of Sparse Linear Systems" (George, Liu, Ng, Oak Ridge National Laboratory, 1994) is implemented here.

Template Parameters
IndexTypeType of the indices of all matrices used in this class

Member Function Documentation

◆ generate()

template<typename IndexType = int32>
std::unique_ptr<permutation_type> gko::experimental::reorder::Rcm< IndexType >::generate ( std::shared_ptr< const LinOp system_matrix) const

Note
This function overrides the default LinOpFactory::generate to return a Permutation instead of a generic LinOp, which would need to be cast to Permutation again to access its indices. It is only necessary because smart pointers aren't covariant.

◆ get_parameters()

template<typename IndexType = int32>
const parameters_type& gko::experimental::reorder::Rcm< IndexType >::get_parameters ( )
inline

Returns the parameters used to construct the factory.

Returns
the parameters used to construct the factory.

The documentation for this class was generated from the following file: